Absorbent tissue products such as paper towels, facial tissues, bath tissues and other similar products are designed to include several important properties. For example, the products should have good bulk, a soft feel and should be highly absorbent. In addition, the products should also have sufficient strength for the particular application and environment in which they are to be used.
In the past, those skilled in the art have developed various processes for enhancing and improving various properties of tissue products. For example, in order to increase bulk and improve softness, tissue products have been subjected to creping processes. For example, in one embodiment, a creping adhesive is sprayed onto a rotating drum, such as a Yankee dryer. A tissue web is then adhered to the outside surface as the drum is rotating. A creping blade is then used to remove the tissue web from the surface of the drum. Creping the web from the drum foreshortens the web and can break fiber to fiber bonds which both increases the bulk and softness of the product.
In United States Patent Application Publication Number U.S. 2008/0073046, which is incorporated herein by reference, a creping process as described above is disclosed that is useful for not only creping tissue webs, but can also be used to incorporate beneficial additives into the tissue sheet during the creping process. In particular, the '046 application teaches applying an additive composition to the surface of a creping drum that adheres the sheet to the surface of the drum. During creping, the additive composition transfers to the tissue sheet in amounts sufficient to improve at least one property of the tissue sheet. The additive composition can comprise, for instance, a thermoplastic polymer resin, a lotion, a debonder, a softener, and the like.
Applying additives as described above to tissue sheets may improve various properties of the sheets. Unfortunately, however, some of the additives may have hydrophobic characteristics and thus may have a tendency to interfere with the ability of the tissue sheet to absorb fluids, such as water. Thus, even though the inventions described in the '046 application provide great advancements in the art, further improvements may be needed. For instance, a need exists for a process for applying an additive composition to a tissue sheet during a creping process that leaves untreated areas on the sheet for allowing uninhibited liquid absorption.